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1 <br /> Site Background Information Chapin Brothers Investements, Inc <br /> Page 4 of 12 <br /> Converting these values to parts per million volume(ppmv),concentrations ranged from 9,800 ppmv <br /> ' (at 6 hours) to 15,680 ppmv (at 12 hours) Generally, a vacuum of 0 10 is required to successfully <br /> volatilize subsurface hydrocarbons The maximum vacuum measured at each well was plotted <br /> versus the distance of each well from the extraction well Drawing a"best fit"line through the three <br /> data points will determine the effective radius of influence at this site, the effective radius of <br /> influence at the site appears to be approximately 37 feet It appears that vapor extraction,using an <br /> IC engine, would successfully remove a significant volume of petroleum hydrocarbons from <br /> unpacted soil at the site Furthermore, it is likely that extraction on VE-2 (slant boring)will have <br /> a positive influence on impacted soil in the vicinity of MW-3 <br /> Dissolved oxygen and ground water depth data collected during the pilot study indicate that IAS, <br /> combined with SVE should provide a viable alternative for remediation of impacted ground water <br /> at the site <br /> ' The ground water depth was increased (depressed) as much as 144 feet in ASO-1 located <br /> ' approximately 3 feet from AS-1),groundwater depth decreased as much as 0 20 feet in ASO-2 No <br /> significant change in ground water depth was anticipated in ASO-3 and therefore, ground water <br /> depth was measured only once Dissolved oxygen in ground water was measured in the IAS <br /> ' observation wells at several intervals throughout the IAS test In ASO-1,dissolved oxygen ranged <br /> from 84 1%to 87 4%, in ASO-2,dissolved oxygen ranged from 16 0%to 32 9%, dissolved oxygen <br /> was measured at 62 4%in ASO-3 It appears that the effective radius of influence for the air sparging <br /> ' wells on-site may be as great as 20 to 30 feet <br /> The increased dissolved oxygen and the change in groundwater depths indicate that the injected air <br /> ' had an influence on all IAS observations wells at the site Although the concentration of petroleum <br /> hydrocarbons increased in two of the three observation wells,this may be a results of desorption of <br /> hydrocarbons from the impacted soil in the smear zone or sample collection techniques <br /> 1 <br /> REMEDIATION WELL INSTALLATION <br /> On 19 April 1997,one additional SVE well,VW-7 was installed at the eastern edge of the site to a <br /> depth of 15 feet Also six to-situ air-sparing (IAS) points point were installed using two 21-inch <br /> ' long, %-inch I D stainless steel screen implants attached to an anchor tip at 30 feet bsg (IAS-2 <br /> through IAS-7)were installed to depths of 30 feet bsg using AGE's van-mounted Geoprobe 5400 <br /> soil probing machine Two probe borings were completed as IAS points using one 21-inch long,3/8- <br /> inch I D stainless steel screen implant attached at 26 feet bsg to an anchor tip Vinyl tubing(3/8-inch <br /> 0 D )was extended from the sparging screen implant to the surface and a filter pack (fine glass <br /> beads)was installed around the screen implant from a depth of 25 to 30 feet bsg Bentonite sand(#8 <br /> bentonite)was used to make a 4-foot plug above the filter pack and the wells were grouted to surface <br /> grade with portland cement An eight-inch traffic box was installed at the surface for each IAS point <br /> ' Advanced GeoEnvironmental,Inc <br />